The trial of Bruce Beresford-Redman in Cancun, Mexico came one step closer to resolution on Thursday.

A former reality TV producer for “Survivor” and other shows, Beresford-Redman stands accused of killing his wife Monica at a Cancun resort in 2010, in a case that generated international headlines. A court-appointed crime scene expert testified in court Thursday that he could not find any forensic evidence linking Beresford-Redman to his wife’s death.

With that, the expert dealt a blow to the Mexican prosecutor’s case. Beresford-Redman then invoked his Mexican constitutional right to request an end to his trial. Cancun prosecutors will oppose that and request the trial to continue. In a statement, the prosecution said that despite the latest testimony there are elements pointing to Bruce Beresford-Redman's guilt. The victim's sisters Jeane and Carlos Burgos issued their own statement to the judge in the case, saying "we urge you not to set the man who murdered our sister free."

Beresford-Redman’s defense attorney Jaime Cancino told Dateline NBC he is optimistic his client will eventually be released: “We believe at the end of the day, when this trial concludes, our client will be absolved.” Beresford-Redman’s murder trial in Cancun has been ongoing for nearly two years, since February 2012. Mexican prosecutors have called witnesses and presented evidence they said would prove Beresford-Redman killed his wife. The Judge in the case could render a verdict in the case in the next few months.

Last month Beresford-Redman’s mother Juanita provided Dateline with a new statement from her son: “The situation is intolerable. I need to be home with my children. I am an innocent man, and my life has been destroyed.” In a phone interview, Mrs. Beresford-Redman said her son is “angry more than anything else. There are days when he’s really down, but by and large he’s ok.”

It all began with a family vacation back in April 2010. The Beresford-Redmans traveled with their two young children from Los Angeles to Cancun for a spring break at the luxurious Moon Palace Resort. Eight days later, Monica Beresford-Redman’s body was found inside a sewer cistern on the resort grounds. Autopsy results indicated she had been strangled.

As police investigated, they learned that Bruce Beresford-Redman had recently had an extra-marital affair, and that hotel guests had reported hearing screams coming from the Beresford-Redmans’ room before her body was discovered. Police also found blood on a pillow in the Beresford-Redmans’ hotel room.

The victim’s sisters, Jeane and Carla Burgos, were highly suspicious of their brother-in-law and his behavior. “We really think that if he was not guilty, he would act totally different from what he did,” Carla Burgos told Dateline, for a February 2012 program chronicling the case. During the investigation, the State Attorney General in Cancun, Francisco Alor, stated that “everything in this investigation is revolving around Bruce.”

Monica Beresford-Redman (victim).

On April 9th, 2010, one day after Monica Beresford-Redman’s body was found, Mexican police declared her husband a “person of interest” in her death and instructed him to stay in Mexico as they investigated. But Beresford-Redman left the country, and on May 23, 2010, returned to Los Angeles, trailed by media cameras as he maintained his innocence. Shortly after his return to the States, Mexican police issued a warrant for his arrest. After a two-year extradition process, a U.S. federal judge in Los Angeles ruled that Mexico had produced sufficient evidence for Bruce Beresford-Redman to stand trial for murder.

In February 2012, U.S. Marshals handed him over to Mexican authorities to face a court in Cancun.

Beresford-Redman’s trial has been held in fits and starts since his extradition. But Beresford-Redman’s attorney tells Dateline he believes this latest crime scene expert’s testimony illustrates that the prosecution’s case against his client has fallen apart. Cancino says some alleged physical evidence in the case was lost, or perhaps destroyed, before the defense could examine it. And he says the prosecution has failed to produce several key witnesses in the case, including the guests who allegedly heard screams coming from the Beresford-Redmans’ room.

Cancino says the guests were never even interviewed by investigators. “My opinion is that the prosecution made a lousy criminal investigation,” Cancino told Dateline. “Since the beginning it was focused to Bruce, instead of doing a professional and open investigation.” The State Attorney General, whose office oversees the prosecution, did not comment directly on the defense’s case but said in a statement that the judge will have the final word once he weighs all the evidence.

Back in California, Bruce Beresford-Redman’s parents have been taking care of their son’s two young children since his arrest. Juanita Beresford-Redman says when they speak to their father over the phone, he works hard to keep his spirits up, and theirs: “When he talks to the children, you’d think he’s coming home tomorrow.”